The surge in the demand for communication services has resulted in the popularization of information and communication services and the introduction of various multimedia services and high-quality services. While the number of subscribers to mobile voice call services is reaching a saturation point, the number of subscribers to various additional services is increasing.
Global system for mobile communications (GSM), which is a second-generation (2G) communication network, and wideband code division multiple access (WCDMA), which is a third-generation (3G) mobile communication system, support ‘terminal mobility’ through a subscriber identity module (SIM) card or a universal subscriber identity module (USIM) card which is inserted into a terminal. Here, the term ‘terminal mobility’ refers to the capability of changing terminals by inserting a USIM card, which includes subscriber information, into any terminal which supports third-generation or next-generation mobile communication services. Therefore, instead of being restricted to a certain terminal, users can have terminal mobility, that is, freely change terminals by inserting their USIM card into desired terminals. A SIM or USIM card is a smart card inserted into a WCDMA terminal and has various functions such as user authentication, global roaming, and e-commerce. In an environment that supports terminal mobility, users can frequently change terminals by using their SIM card or USIM card. Thus, services that can be provided may depend on hardware specifications of each terminal. Terminal mobility in IP multimedia subsystem (IMS) network can be supported by using an ISIM (IP multimedia subscriber identity module) card.
Generally, a user inserts his or her SIM, USIM, or ISIM card into a user terminal and uses the user terminal. When the user turns on the user terminal, the user terminal begins its location registration, and an equipment identity register (EIR) authenticates the user terminal. If the user terminal is registered as a stolen terminal, the EIR does not allow the location registration of the user terminal.
However, when a user terminal is lost or stolen, it is often not immediately blacklisted after it was lost or stolen. It usually takes some time for a user of the user terminal to recognize and report that the user terminal was lost or stolen. Thus, a person, who obtained the user terminal in the meantime, can insert his or her SIM card into the user terminal and use the user terminal.
Since the EIR authenticates a user terminal when the user terminal is turned on after being turned off, if a person who stole the user terminal, which is turned on, does not turn off the user terminal, there is no way to prevent the person from using the user terminal.
In this regard, a method and system, which can prevent the use of a stolen terminal even when the stolen terminal remains turned on, is required.